This invention relates to a reinforcing apparatus applied to the exterior of a monopole supporting a communications antenna array having a plurality of rods connected to adjustable brackets for providing additional strength along the length of the monopole sufficient to overcome the force moment from additional weight and wind shear.
In response to the increased number of cellular telephone users, wireless communication providers are expanding wireless services. One of the ways to meet the needs of the cellular telephone users is by constructing new antennae bearing monopole towers, often referred to as cell sites. However, local zoning laws often prohibit the construction of new cell sites except in certain pre-designated areas which may not provide sufficient coverage for the expanding wireless services. To circumvent this problem, wireless communication providers are placing additional antenna systems on existing monopole towers. Since already erected monopole towers were not designed to safely support the additional antenna loads, these towers must be reinforced to not only provide the needed support for the additional antenna load, but also the additional forces the wind and other environmental conditions will exert on the monopole tower due to the increase in the surface area presented by the added antenna array(s).
One method for reinforcing monopoles is by overlaying a new outer steel skin over the existing monopole. This type of procedure is exceptionally expensive and laborious, since the new outer steel skin must be fabricated to fit the existing monopole with small tolerances for dimensional error. The installation of this type of reinforcement is inefficient in that placing the new outer skin over the existing pole requires many field personnel and large cranes to accommodate the weight of the overlay pieces.
Another way monopole towers have been reinforced is by welding bar, angle or tubular steel sections to the exterior surface of the monopole. Although the addition of the steel to the monopole will increase the strength, the process is extremely labor intensive, costly, and greatly reduces the integrity of the galvanized steel in the monopole to resist rust, which will eventually compromise the strength of the monopole.
Already erected monopoles have also been strengthened by constructing metal lattice-work structures around the existing monopole tower. Such lattice structures often require more land, are aesthetically displeasing, and are expensive and time consuming to erect.
Additionally, another known method utilizes hollow steel rods which extend along the length of the monopole and are attached by way of a conformed mounting bracket having an arc length of fixed diameter corresponding to the diameter (or circumference) of the monopole at the point of attachment. In most cases, monopoles are gradually tapered from the base to the top, wherein the diameter at the base of the monopole is larger than the diameter at the top. This taper poses a problem for mounting brackets having a fixed diameter, in that brackets must be custom made, having a specific diameter closely matching the arc length of the erected pole, to provide reinforcement at particular locations along the monopole. In order to attach the rods along the monopole, a variety of mounting brackets having differing diameters must be used. Manufacturing custom made mounting brackets and utilizing numerous differently sized mounting brackets to fit particular locations along the length of the monopoles is not only expensive, but also labor intensive and time consuming.
Thus, there is a need in the field of monopole reinforcement, to provide a cost effective, aesthetically pleasing, durable and simple way to adequately reinforce and strengthen monopole towers.
The present invention is directed to a reinforcement apparatus forming a total or partial exo-skeletal frame for support directly upon the surface of an existing erected monopole tower to provide additional stability and strength to resist the force moment from wind resistance caused by the increased surface area and weight loading of additional antenna arrays through the use of a series of adjustable mounting clamps and associated perimeter support rods.
More particularly, the present invention is drawn to a cost effective and efficient way to provide stability and resistance to deflection to already erected tapered monopole towers by constructing a simple and inexpensive reinforcement apparatus circumscribing a monopole structure at varying heights from the base and having adjustable mounting clamps and perimeter support rods positioned on and along the surface of the monopole. The mounting clamps have adjustable spacings to easily fit around the monopole at any position along the entire length (height) of the pole. Connecting the adjustable mounting clamps are a series of perimeter support rods, which extend along the length of the monopole tower in close proximity to the outer skin of the pole.
As the preferred embodiment of the present invention, a reinforcement apparatus for a monopole structure comprises a plurality of support rods and at least two adjustable mounting clamps having guide tubes extending along and in close proximity to the outer skin of the pole. The plurality of support rods have first and second ends with each respective end of the support rods receiving one of the plurality of guide tubes. The adjustable mounting clamps comprise a plurality of interconnecting brackets connected to one another by length adjustable attachment members. Although differing adjustable attachment members can be used in the present invention, threaded rods and nuts of sufficient strength are preferred.
The plurality of interconnecting brackets include a steel plate having a flat central portion, first and second ends set at angles with respect to the flat central portion with the guide tube being attached onto the flat central portion. The outside dimension of the plurality of guide tubes are nearly the same or slightly smaller than the inside dimension of the plurality of perimeter support rods so as to provide a snug fit upon insertion of the guide tube into the support rod. Although the guide tubes can be limited to extend in a single direction from the bracket, guide tubes extending in opposing directions along the monopole structure are preferred.
Additional reinforcement can be incorporated into the preferred embodiment of the present invention by the reinforcement apparatus circumscribing the monopole structure and comprising a plurality of support rods having opposing ends and extending along the monopole structure to at least three adjustable mounting clamps at each end of the guide tubes, such that each adjustable mounting clamp has a plurality of guide tubes extending in opposing directions along the monopole structure which are inserted into and attached to the ends of the plurality of support rods. The adjustable mounting clamps comprise a plurality of interconnecting brackets connected to one another by length adjustable attachment members.
Alternatively, the present invention is also directed to a method for reinforcing a tapered monopole tower. This method includes the steps of attaching and loosely securing a first set of at least two adjustable mounting clamps, having guide tubes thereon, to and around the monopole tower at a predetermined height from the base and separated a distance apart from one another, connecting a set of support rods to one of the adjustable mounting clamps by inserting the guide tubes into respective cooperating ends of the set of support rods. The method next includes the steps of attaching and loosely securing a second set of at least two adjustable mounting clamps and inserting the guide tubes of one of the second set of adjustable mounting clamps into the other respective cooperating ends of the set of support rods and tightly securing the plurality of support rods to the adjustable mounting clamps by inserting affixing members therein. The method next includes the tightening of both first and second sets of adjustable mounting clamps to retain the support rods in close proximity over the desired outer skin area of the monopole tower.
Additional reinforcement can be supplemented to the described method of the present invention by attaching additional sets of adjustable mounting clamps at different heights to the monopole tower. The supplemental method includes the steps of inserting the guide tubes on the additional adjustable mounting clamp sets into the respective cooperating ends of the additional sets of support rods and tightly securing the plurality of support rods to the adjustable mounting clamps by inserting affixing members therein. The supplemental method next includes the tightening of the sets of adjustable mounting clamps to retain the support rods in close proximity over the desired outer skin area of the monopole tower.